Blue Planet II reached over 37m people in the UK alone. Following the final episode, over 60% of people surveyed commented that they wanted to make changes to their life to reduce the impact on the ocean.

The response, said Attenborough, has left him “absolutely astonished.”

“We hoped that Blue Planet II would open people’s eyes to the damage that we are doing to our oceans and the creatures that live in them. I never imagined that there would be so many of you who would be inspired to want change.”

Professional skill, time, money and the latest camera technologies are all vital to making landmark natural-history shows. Less well known, when it comes to seeking unique footage of life deep in the world’s oceans, is how programme-makers put their health on the line.

The lengths that these men and women go to in the cause of producing iconic TV was explained in detail during an RTS event, “Diving beneath the waves – the making of Blue Planet II”.

Sarah Conner, an assistant producer on the landmark show that generated record ratings for BBC One, revealed how she had knelt on the bottom of the ocean for eight-hours at a time. There in the dark depths diving rebreathers in sub-zero temperatures she would direct cameraman Hugh Miller.

It is one year on from one of the biggest and most controversial shake-ups in BBC history – the £400m formation of BBC Studios. Now, the BBC is ruffling feathers again as it merges this recently created commercial production division with BBC Worldwide to create a single company with revenues of £1.4bn.

Each episode will follow an individual animal – lions, hunting dogs, chimpanzees, tigers and emperor penguins – at the most critical period in their lives as they navigate the world’s rapidly changing habitats.

This series will show for the first time what an animal must do to create and maintain a dynasty, and leave a legacy in nature.

Made by the team behind Blue Planet II, the most watched programme of 2017, the BBC aims to recapture its success with new ‘intimate animal dramas’.

As BBC Studios’ Natural History Unit turned 60 this autumn, 2017 was a particularly exciting and busy year. But I was nervous about whether Blue Planet II would equal the impact of Planet Earth II almost a year previously.

In November 2016, Planet Earth II attracted record TV audiences in the UK; the series went on to win RTS, Bafta and Emmy awards. That sequence of racer snakes hurling themselves at hatchling marine iguanas won a Bafta for TV’s most memorable moment.

The trailer, titled The Prequel, features David Attenborough's narration over spectacular scenes of the Earth's oceans and the underwater inhabitants.

The five minute clip teases what is in store for the long-awaited sequel to the 2001 nature series; from slow-motion shots of blue whales soaring out of the ocean, to a glimpse of a bale of turtles occupying an entire beach as they slowly make their way to the sea, to close-ups of the extraordinary creatures on the sea floor.